a) Field of the Invention
The invention is directed to an arrangement for the manual adjustment of a focus position in microscopes with a motor-operated focusing drive.
b) Description of the Related Art
An essential prerequisite for observation through a microscope is the adjustment for the sharpness of the specimen section to be observed. In the classic microscope design, the focusing movement required for adjusting the sharpness of a specimen section to be observed is realized by means of gear units which have high gear ratios and a high sensitivity of adjustment.
The focusing movement can be initiated manually, for example, by turning a drive knob which transmits the rotational movement via a spindle-nut adjusting device to the stage or to the microscope housing and accordingly causes a relative movement between the microscope body and specimen.
However, in other common focusing arrangements the positioning of the specimen relative to the microscope body is realized by a stepping motor which is controlled in a definite manner. Both the adjusting speed and adjusting path are determined by the control. The invention described in the following also belongs to this technical field. The speed of the focusing movement and of the adjusting path in a desired direction of the focusing movement are given by control commands by means of operator's controls which are actuated manually.